Facile Synthesis of Silver Nanoparticles Using Lantana trifolia Aqueous Extracts and Their Antibacterial Activity

Synthesis of metallic nanoparticles using secondary metabolites present in plant extracts has attracted attention. In this study, Lantana trifolia aqueous extracts were used to synthesize silver nanoparticles (AgNPs) which were then screened for their antimicrobial activity. The morphology, size and functional groups present in AgNPs was evaluated using electron microscopy and Fourier transform infrared spectroscopy (FT-IR). The role of temperature, reaction time and concentration of precursor ion were evaluated by measuring the surface plasmon resonance of AgNPs using UV–Vis spectroscopy. The crystal structure, hydrodynamic diameters and redox potential were evaluated using powder X-ray diffractometer (PWXRD), dynamic light scattering (DLS) and cyclic voltammetry respectively. The data obtained in this study revealed that increase in the reaction time led to an increase in surface plasmon resonance of AgNPs while the increase in temperature from 20 to 35 ℃ increased the rate of AgNPs synthesis. The XRD diffractogram revealed that the particles were composed of silver with 2θ = 38.36, 44.428, 54.89, and 57.87, corresponding to the silver crystal planes of (111), (200), (220), and (311). The diameters of the nanoparticles were between 35 and 70 nm, and they had moderate antimicrobial activity against E. coli, P. aeruginosa, C. albicans, S. aureus and B. subtilis.